Abstract

Background, aim, and scope

Packaging uses nearly 40% of all polymers, a substantial share of which is used for sensitive merchandise such as moisture-sensitive food. To find out if bio-based materials are environmentally advantageous for this demanding application, we compared laminated, printed film across the whole life cycle.

Materials and methods

We compared bio-based materials (paper, polylactic acid, bio-based polyethylene, and a bio-based polyester) as well as conventional ones (polypropylene, polyethylene). Data stemmed from 13 companies that produce raw materials, films and/or laminates and which co-operated with us in a project commissioned by a large food producer. The functional unit chosen for this study is 1 m2 of packaging film. This is (mostly) laminated, printed film that is delivered on reels to the food industry, where the laminate is cut, sealed and filled. The impact assessment is presented for non-renewable energy use, total energy use, global warming potential, depletion of abiotic resources, photo-oxidant formation, acidification, eutrophication, water use, and land use.

Results

For Inner Packs that get in direct contact with food and therefore require certain barrier properties, the environmental performance of many laminates is not better than the reference, petrochemical material. However, our study shows that paper/polypropylene laminates perform equally well as the current material (polypropylene) if the material is landfilled, and better if incinerated with energy recovery. For Outer Packs, bio-based polyethylene film shows a particularly low environmental impact. Paper/bio-based polyester laminates also offer significant savings compared with the current material. For Inner as well as Outer Packs, laminates including polylactic acid offer environmental advantages when accounting for wind credits or when assuming a future technology level for polymer or film production.

Discussion

Increased technology maturity of PLA and cellulose in the film production stage offers significant environmental improvement with respect to global warming potential compared with today’s technology. Though large, the uncertainty regarding the degree of degradation of paper, cellulose, PLA and bio-based polyester, is not decisive for the conclusions.

Conclusions and recommendations

Generally, laminates and films (partly) consisting of bio-based polymers offer opportunities for significantly reducing environmental impacts of food packaging. Large variations in land-use are possible depending on the type of bio-based material that is used. The environmental advantages differ depending on the polymer and the final product (Inner vs. Outer Pack). Lack of experience and investment in converting bio-based polymers into final products and comparatively unfavourable material properties result in lower environmental advantages for some novel bio-based materials than one may expect. However, a) already today, the options with the lowest global warming potential are partly or fully bio-based and b) bio-based materials will benefit more from technological progress than conventional materials, potentially making certain bio-based laminates highly attractive options for the future. Overall, Outer Packs are more promising than Inner Packs when introducing bio-based wrappings to replace the current petrochemical material because a) the opportunities are clearer for this application and b) the product specifications (required barrier properties) are less demanding. Starting with the Outer Packs would also allow bio-based polymer producers and processors to invest and learn, thus offering the opportunity to reduce the environmental impact even further.